Such helmets are known to offer a dual configuration, namely:
an “integral” configuration in which the chin guard is closed at the front of the helmet and provides protection for the facial portion of the chin, and
a “jet” configuration in which the chin guard is open and placed on the back of the helmet, beyond the top of the shell, in order to clear the face of the wearer while keeping the helmet in place on the skull, while preventing having a protruding chin guard in open position for, on the one hand, preventing severe injuries of the neck of the wearer in the event of a fall and locking by friction against the ground or other obstacles and, on the other hand, to optimize the aerodynamic feature of the helmet in the open position of the chin guard.
It is thus known from document EP 1 806 986 to design a protective helmet in which the chin guard has two lateral branches each provided with a guide in which is meshed at least one guiding finger fixed on the shell, in such a manner that the chin guard slides along these guiding fingers between the open and closed positions, and the shield has two lateral arms articulated on the shell.
In order to guarantee the sealing of the helmet in <<integral>> configuration, this document EP 1 806 986 proposes that the shield when lowered, bears against an upper outer edge of the closed chin guard, and the chin guard collaborates with guiding means shaped for guiding the latter along a not entirely circular trajectory which, combining rotation and translation, along which the chin guard moves away from the shell and tips towards the back by passing over the shield to its open position.
This particularly advantageous solution however has a drawback, namely that when the chin guard is in open position and the shield is in lowered position, the wearer must manually lift the shield in order to allow the chin guard to return to the closed position.
This manual lifting of the shield, prior to closing the chin guard, has a drawback in terms of safety. In fact, if the wearer wishes to bring his/her chin guard towards the front in closed position, while driving, he/she must carry out two movements, namely lift the shield then tip the chin guard towards the front, thus contributing in increasing the handling time and reducing vigilance during the time of the operation.